Making rounded dips in cylinder
As you model a glass bottle, you'll probably want to have caustics taking into account all those bumps on a mesh. Hence in this case those parts should be part of geometry and thus modeled.


Extruded base object (circle) has 24 vertices for overall roundness of final mesh provided that additional loops needed for details. Select edge loop where curved bumps will be. Deselect every other vertex of the loop (you can use Checker Deselect for that); use curvature for reference. Selected vertices will represent the rounded bumps of the bottle. 
Scale them along normals (Alt+S) and grab in the opposite side from the sticker (so if you work with the loop lower than sticker, grab selection down). Do the same for all other loops where you'd like to have roundish bumps.
Make sure to convert all other edge loops into perfect circles for preserving correct form of the bottle (select them one by one and choose Circle operator from W > Looptools menu; note that Looptools addon should be enabled for that). After adding Subsurf modifier (on the 2-nd level of subdivision) scaled parts will be subdivided good enough so non-planar Ngons won't cause any problems here.




Most likely you'll also want to add thickness to the mesh in order to have better caustics. The only thing with adding Solidify modifier in this case is that you'll need to apply it and then use W > Looptools > Circle once more, but this time on the edge loops created with modifier (they will be copied from the outer curved loops and hence may refract light in an unexpected way).